Ultra High Rotating Tune-Up Motor Air cooled 2 holes Ultimate high torque, great strength in cornering Size: 1.0 x 0.8 inches (25 x 20 mm), Shaft Diameter: 0.08 inches (2.0 mm), Torque: 0.8 oz (21.5 g), Suitable Voltage: 2.4 - 3.0 V.
(From Amazon.co.jp)